During the melting of a slab of ice at 273K at atmospheric pressure,

Options

A. positive work is done by the ice water system on the atmosphere
B. positive work is done on the ice water system by the atmosphere
C. the internal energy of the ice water system increases
D. the internal energy of the ice water system decreases

Answer

To solve the question regarding the melting of a slab of ice at 273K at atmospheric pressure, we will analyze the thermodynamic processes involved.

### Step-by-Step Solution:

1. **Understanding the Process**:
- The melting of ice at 273K (0°C) is a phase change from solid (ice) to liquid (water) at constant temperature and pressure.

2. **Temperature and Internal Energy**:
- During the melting process, the temperature remains constant at 273K. However, the internal energy of the system increases because energy is absorbed in the form of heat (latent heat of fusion) to break the bonds between the ice molecules.

3. **Volume Change**:
- When ice melts, it transitions from a solid state to a liquid state. The volume of water is less than the volume of ice, which means that the volume decreases during the melting process. Thus, we can say that the change in volume (ΔV) is negative (ΔV < 0).

4. **Work Done**:
- The work done (W) in a thermodynamic process can be expressed as W = -PΔV, where P is the pressure. Since ΔV is negative, the work done by the system (ice melting) on the surroundings is positive. This means that work is done on the surroundings by the ice as it melts.

5. **Conclusion**:
- Therefore, during the melting of ice at 273K:
- The internal energy of the system increases.
- The volume decreases (ΔV < 0).
- The work done by the system (ice) on the surroundings is positive.

### Final Statements:
- The internal energy of the system increases.
- The volume change is negative (ΔV < 0).
- The work done by the ice on the atmosphere is positive.